Internal wiring question on E3L dynamo.

[Billybream]

Just purchased tidy looking dynamo, upon inspection, with alloy end cover removed, the internal wire from field coil was loose together with one of the brush wires. The other two were joined to alloy end cap with terminal fixing. Can,t see what's missing to connect the two loose wires together. Any help appreciated.

[beezermacc]

Looking directly at the end of the dynamo, and if the dynamo is wired typically the following is how it is wired. The two wires which come out through the top of the brush carrier plate are the field coil wires.  Normally the wire which exits through the right-hand hole has a small sleeve on it and is earthed with a small screw just above the bearing. The left hand field wire is connected to 'F'. The left hand brush is earthed with the right hand field wire. The right hand brush goes to 'D'. Before testing, flash the dynamo (negative lead of a battery to 'F' and positive lead of battery to earth -  a quick tickle(!) should be all you need). Connect F and D together with a bridge wire. Connect any point of the bridge wire to a 12v bulb, then the bulb to earth on the dynamo. Then spin the dynamo anticlockwise with a drill to test. Bulb should glow very brightly at about 1400 r.p.m. If all is well remove the bridge wire before putting to use.

[Billybream]

Thanks Beezermacc for your reply.
Went back to the seller and he replied : In the mid 50,s Lucas changed the type of end cap, early ones used steel strap, the terminals were on the bakerlite end plate. Later types replaced the steel strap  and bakerlite end plate  with a cast alloy end cap, the terminals moved to the compressed cardboard brush plate.
He goes on to offer me some brass set screws to use as the terminals, after drilling the brush plate.
I think I was expecting later type of dynamo as picture showed the alloy end cover, sounds like I have been supplied hybrid.
I,m now confused how to connect the two wires from the wiring loom.
My existing set up have support plate with push in type connections and securing screw.
Feeling I should have sent my existing dynamo to specialist for overall.

[duTch]

 I'm curious to see a visual of how this originally was? 

the terminals moved to the compressed cardboard brush plate.

, as I have the ally cover on an earlier body, which I think does have a groove for an 'O' ring, so maybe not much earlier..??
  It's a bit busy/crowded in there with bullet connectors in use..!

 I suggest that the two wires in question are attached to the cover as an earth connection, but not a very good (soft) one...?? My piccie shows where they should attach to.

  Also B'macc, Question- I know we've been over this before, but I'm thinking to switch to -ve Earth, to save me confusion, so just checking as you say only the Field wire needs to connect to '-ve' battery? I've been told all kinds of things over the years mainly join 'D' and 'F' for polarizing also. Does it matter if 'D' joins the party or not?

   It just seems too easy, makes me suspicious..!!

[beezermacc]

The easiest thing to do is use a chocolate block connector. There's enough space in there. Just make sure the field coil wire labelled 'F' is connected to the 'F' terminal on your regulator., and the 'D' wire from the brush to your'D' terminal on your regulator. This is not something I would normally do as I like things to be original, but it will get you going. You can get in touch with me using my contact details off my website. It might be easier to talk about it. www.priorymagnetos.co.uk

[beezermacc]

  Also B'macc, Question- I know we've been over this before, but I'm thinking to switch to -ve Earth, to save me confusion, so just checking as you say only the Field wire needs to connect to '-ve' battery? I've been told all kinds of things over the years mainly join 'D' and 'F' for polarizing also. Does it matter if 'D' joins the party or not?

   It just seems too easy, makes me suspicious..!!

The purpose of flashing the dynamo is to polarise the magnet which the field coil is wrapped around. The magnet is made out of soft iron and is very weak which is why, when a dynamo is left standing for a long time, it won't work, i.e the magnet has lost its magnetism completely and cannot influence/energise the rotating armature. When connecting a battery to the field coil circuit you are making a basic solenoid or electromagnet. The magnetic poles of the magnet will be determined by the way the current is flowing through the field coil wire. Switching the poles of the magnet also switches the polarity of the dynamo's charge. It is that easy and 'D' does not need to be involved.

[duTch]

 Ok Thanks, it's like stuff I was taught in school- maybe I learned some of it.. .....maybe that's why I'm suss

 I can recall the first time I was told of 'flashing' ..weirdo......nah-jokin', but it makes sense that the armature doesn't need polarizing too, as the way I understand, it creates its' own as it goes around, so one magnet crossing the other does the magic...?


 

[Billybream]

Sorted now, going to fit later type brush plate, to match my wiring termination. Thanks for advice.

[duTch]

 Billy, do mind posting a picture of it when yoe get it...?? ta in advance

[wilko]

I've never seen the later brush plate for sale.

[nimrod650]

hi if you have any problems on mags or dynamo.s or require any a10 spares contact andrew rocker priory magnetos maccelsfield cheshire they are the most helpful people  you could ever wish to deal with

[Billybream]

Later type brush plate available on EBay Uk, new one without any terminals and used one complete. Fortunately I have some salvage bits I can rivet on. Its amazing what we keep, but how they help you out in maintaining our BSA,s.

[Billybream]

Modified new old replacement dynamo with my old brush plate. Tested out on bench with electric drill and got output.
Fitted to bike together with new belt drive conversion from Dynamo Regulators. All OK good charge rate, using existing mechanical regulator. Fitted new DVR2 and no output, checked usual things but still no still no joy. So onto this forum and picked up tip about flashing dynamo and bingo like magic now have fully working system.
Most impressed with Dynamo Regulators kit of belt drive and DVR2 regulator, easy fit, with good instructions and quality parts.